Closure cap and method of making the same



Feb. 11, 19411 E. a. KRAMER ETAL 190 CLOSURE CAP AND METHOD OF MAKING THE SAME Filed Feb. 20, 1933 4 She'ets-Sheet l 1 E. B. KRAMER ETAL 2,231,190

CLOSURE CAP AND METHOD OF MAKING THE SAME Filed Feb. 20, 1933 4 Sheets-She et 2 ll lllllllllll "IIIIIIIIII/IlIlIIIIII/n lll llll III'IlllII/llIII/III I III 1111111111111,

Feb. 11, 1941- E. a. KRAMER EI'AL ,2 1

CLOSURE CAP AND METHOD OF MAKING THE SAME Filed Feb. 20, 193: 4 Shgets-Shqat s 'Feb. 11, 1941i I E. B. KRAMER EI'AL 33 CLOSUREVCAP AND METHOD OF MAKING THE SAME Filed Feb. 20, 1953 4 Sheets-Sheet 4 IZ m Patented Feb. 1 1, 1941 UNITED STATES PATENT OFFICE-- CLOSURE CAP AND inn-non F MARIN m SAME Application February 20, 1933, Serial No. 657,734

. 4 Claims. (01- 215-44) This invention relates to closure caps, and to new and improved methods of making the same.

The cap of the present invention is of the type adapted for use with bottles, jars, or other re 5 ceptacles having external threads or lugs on the necks thereof. More particularly, thecap is of the general class. known in the art as lug caps.

Caps of the lug type are well known, and have been made by many different methods, and have embodied a great variety of different constructionai details. The present cap, when compared with devices of the prior art, has certain fundamental structural diflerences, which result in definite advantages, as will be pointed out below.

It is a primary object of the present invention to provide a cap of the lug type, in which the lugs are hidden from view when the cap is in use upon a receptacle. It is a further object of the invention to provide a cap having lugs concealed within the cap skirt and constructed in such manner that no disfiguring indications or'marks.

appear upon the skirt of the cap adjacent their location.

It is a further object of the invention to provide a cap having a skirt provided with interiorly disposed locking lugs which do not impair the uniformity of appearance of the exterior surface of the cap.

It is a further object of the invention to provide 90 a cap of the concealed, internal lug type in which the material of the cap adjacent the lower edge of the skirt is not deformed to a degree suflicient to injure the lacquer coating which is conventional- 1y applied to'the cap making material before the sameis formed into'the' completed article.

It is a further object to provide 'a'cap' of the type specified, in which no raw edges are exposed so as to be contacted bythe hands of a user, or to engage directly a receptacle thread.

fit is a further object of the invention to provide a new and improved specific lug structure, characterized by great strength and rigidity, in which a turned edge constitutes a reinforcing member,

and serves theadditional function of presenting 45 a rounded thread engaging surface.

In the past many attempts have been made to design and manufacture a commercially satisfactory lug cap having a smooth exterior surface, and provided with inwardly p ojecting lock- 0 ing lugs which are concealed when the cap is on .the receptacle, and the location of which is not v indicated by indentations or other disfiguring -f Fmarks on the exterior of the cap skirt. All of -;;,-these attempts have fallen short of the desired 5 result in one respect.or another. In some cases the lugs were made up of a single thickness of metal, and were defective because of their inherent weakness, or because they presented a raw edge for contact with the receptaclethread;

In other cases the lower edge of the cap skirt 5 was necessarily provided with indentations or other deformations at points adjacent the lugs. In still other constructions, it was necessary to provide an outwardly rolled head on the lower edge of the skirt to hide the lugs, and such bead 1o destroyed the smooth uniform appearance of the cap. Certain prior art constructions, in which the lower edge-of the cap skirt was turned inwardly and upwardly and pressed into a' flat fold or heni in contact with the inner face of the skirt 15 and merging with the bottom of the skirt in a sharp foldline or crease, have been found defective because thelacquer coating on the cap making metal cracks and chips oif along the sharp fold or crease, with a consequent ruinous 20 effect upon the appearance of the completed cap.- By the construction embodied in the cap of the present invention, all of the defects of prior art caps of this general type are avoided, and all of the objects of the invention accomplished, 251

The cap of the present invention comprises a skirt having its lower edge rolled inwardly to form an interiorly disposed, circumferential bead. the cross-sectional curve of which is, at no point, sharp enough to injure the lacquer coating on the cap making material. The cross-sectional curve-which marks the juncture between the lower part of the cap skirt and the inwardly rolled head is constant around the entire circumference of the skirt, and consequently, the lower edge of the skirt presents a uniformly rounded surface, entirely devoid of indentations or other deformed p ts;

The inner surface of the inwardly rolled head is provided at spaced points withinwardly projectcup-shaped blank from which the cap of the present invention may be made; V

Figure 2 is a similar view showing the blank after a preliminary step in the method has been completed;

Figure 3 is a similar view showing the blank after the first bead forming operation has been performed on the edge of the skirt;

Figure 4 is a similar view of the blank after the first lug forming step has been completed;

Figure 5 is a'similar view showing-one form of completed cap;

Figure 6 is a bottom plan view of the cap of Figure 5;

Figure 7 is an elevational view of the cap of the present invention, showing the smooth exterior surface of the same;

Figure 8 is a bottom plan view of a similar cap, showing a somewhat modified form of lug:

Figure 9 is a vertical axial section of the cap shown in Figure 8, taken through the lugs;

Figure 10 is a top plan view, with a portion broken away to expose the modified form of l Figure 11 is an enlarged vertical sectional view of one edge of the cap skirt, corresponding to the step shown in Figure 2;

Figure 12 is a similar view corresponding to Figure 3;

Figure 13 is an enlarged vertical sectional view through the circular head portion after the step represented by Figure 4 has been completed;

Figure 14 is a view similar to Figure 10 but taken on a section through one of the lugs;

Figure 15 is an enlarged vertical sectional view taken through the head portion of the completed cap;

Figure 16 is a similar view, taken through one of the lugs;

Figure 17 is an enlarged sectional View of the completed cap on a receptacle, showing the manner in which the lug engages a receptacle thread;

Figure 18 is an enlarged top plan view, partly in section, showing .a specific lug structure;

Figure 19 is a vertical sectional view of an apparatus which may conveniently be employed for performing the step in the method represented by Figure 2;

Figure 20 is a similar view, with certain parts omitted, showing the first curling die;

Figure 21 is a similar sectional view of the apparatus taken on line Zl-Zi of-Figure 22, and shows the die which performs the preliminary lug forming step;

Figure 22 is a bottom plan view of the die disclosed in Figure 21;

Figure 23 is another vertical sectional view of the apparatus disclosed in Figure 21 but taken on section 23-23 of Figure 22; and

Figure 24 is a. vertical sectional view through the apparatus showing the die which performs the final step in the method, and completes the several cap forming operations.

Two embodiments of the completed cap of this invention are: disclosed in Figures 5 to I0 and. 15 to 18; The cap comprises a top 25', which may be either" flat as disclosed in. several or of dome shape as disclosed in Figures- 19- to 24,, or otherwise formed.

A downwardly depending substantially cylindrical skirt 26 preferably has a smooth exterior surface and merges with the top in a rounded corner, but, of course, any appropriate decorative embossing may be applied to the skirt if det I The skirt is provided around its entire circumference with a uniformly inwardly turned lower edge 21, the cross-sectional curve of which is constant around the circumference of the cap, to present a uniform appearance. The material of the cap interiorly of the rounded edge 21 continues inwardly and upwardly in a roll or head 28. This head is substantially circular in crosssection at all points around the circumference of the skirt except at certain spaced points where the lugs are situated. The head at the latter points is uncurled, or rolled up to a lesser degree, so that it extends radially inwardly further than the adjacent bead portions to provide locking lugs. 7

In Figures 15 and 18 the substantially circular, inwardly turned bead p01'ti0ns 28 are disclosed in section. It will be noted that the crosssectional curve at the lower edge of the cap skirt, between the cylindrical portion thereof and a circumferentially extending line therebelow, such as the locus of all lowermost points 29 on the bead, is constant on all axial sections: This curve is continued on substantially the same radius inwardly from that line to form an inwardly disposed substantially circular closed head along arcuate sections of skirt circumference. In Figures 16, 17 and 18, which show the lug in cross-section, it will be seen that although the outer curve between the skirt and the line of the points 29 is the same as at the bead portions, the cross-sectional shape of the inwardly extendin roll 38 is diiIerent, is somewhat fiattened, or is struck on a circle of large radius. As a result, the end portion of the skirt at these places extends inwardly beyond the adjacent closed head portions and forms locking lugs 31. Freierably the edge of each of the lugs is turned outwardly, as at 32, to provide a concealed edge, to function as a reinforce for the lug, and to present a rounded thread engaging surface 33.

The lug of the present invention has a thread engaging surface which, as stated above, is rounded cross-sectionally as disclosed in Figures 5, 9, i6 and 17. The thread engaging surface is also rounded in a direction circumferentially of the cap, as shown in Figures i, 8, l0 and 18.

It will thus be seen that the skirt of the cap of the present invention is turned inwardly throughout its entire circumference to form a concealed edge, which edge is curled or rolled upwardly to provide a continuous bead, and that the head at spaced points is uncurled, or rolled up to a lesser degree to provide inwardly extending locking lugs. Whereas the head is circular in cross-section and substantially closed along the arcuate sections 28, it is open and ex- It will also he noted that the lugs are herizontally aligned with theintermediate bead sec-.

tions. The bottom of each. of the uncurled portions is aligned with the closed bead portions so that the cap presents a smooth lower edge, and the tops 33 or all of the, lugs are substantially in alignment with the upper surface of the bead portions.

Where in the the cross-sectional shape of the roll atthelugs-isreferredtuasbeing'.

curves; enalargerradiumwemeananyshape, inciuding substantiall flat, which i less sharply curved than the external curve at the lower edge of the cap skirt.

The lugs have been described as'portions of the rolled. end of the Skirt. or bead, which are a uncurled, or rolled up to a lesser degree than the adjacent portions, and these terms must bexunderstood to relate to structure, and notto the method of'manufacture, as the lugs might -be made by curling the entire bead and subsequent- 1y uncurling, or unrolling portions thereof. on the other hand, they may be formed by simply refraining from curling certain portions of the bead as much as other portions are curled. Also, the lugs might conceivably be formed by axially flattening and radially extending certain portions of the head by applying force to the top 7 of the bead, with the bottom supported upon an anvil having a forming groove with a cross-'sec-, tional curve corresponding to the desired uniform curve to be imparted to the exterior of the lower edge of the cap.

In Figures 8, 9 and 10, a cap having a somewhat modifled form of lug is shown. This type of lug may conveniently be formed by a method similar to the method described in this appliication, but differing therefrom in certain respects, as is clearly pointed out in'the co-pending application of Edward M. Enkur, Serial No. 660,927, filed March 15, 1933. The essential difference 7 in the method resides in an additional step, be-

tween the steps disclosed by Figures 3 and 4, which comprises bending outwardly on predetermined arcuate curves, spaced portions of the partially formed head or Such outwardly be'nt portions are then swung inwardly during the course of the step shown at Figure 4. A comparison between Figures 6 and 8 reveals that the essential difference between the two specific forms of lugs is that the one shown 0 in the latter figure is considerably shorter, cir: cumferentially of the cap, than the first form, but has substantially the same radial depth.

The arcuate curve ila of the innermost edge.

of the lug 3| is'struck on a radius which is a great deal shorter than the radius of .-,the arc upon which the inner edge of the lug ii is struck. Since the radial projection of the two lugs is the same, it follows that the number of degrees on the arc of lug ii is greater than on lug ll.

Certain advantages follow in certain cases from having the lug relatively short and deep, as opposed to long and shallow as in theform of Figure 6. It is within the scope of the present invention to make the lug of any desired form 55 and shape, depending upon the particular use to which the cap is to be subjected.

' A comparison between the several figures discloses that, although the lugs of the modified formhave amaterially different shape in plan, they are substantially identical to the first form in section.

A preferred method of making the cap of the present invention is disclosed in the drawings,

having a top 25 and a cylindrical flange 26 is made in a. conventional drawing operation from a sheet of metal usually having a lacquer coating I on its lower surface, or. in some cases, on both surfaces. In the several forming operations which convert the shell disclosed in Figure 1 into the completed cap of Figure 5, the blank is preferably positioned upside down, as shown, and is moved step by step from one press to the next. The general plan-of the machine forms no -7 -part of the invention of the present application,

ai slightly inwardly'bent position.

and will now be described. A cup shaped blank.

and consequently the specific means for simultaneously moving a plurality of blanks in a step-by-step motion to the various stations is not disclosed.

The blank of Figure 1 has a substantially cy- 5 lindrical skirt 26, terminating in a raw edge 35, which normally is slightly outwardly flared when the blank comes from the drawing dies. Since in the present method it is necessary to curl the end portion of the skirt inwardly, it has been found 10 expedient to first start the curl by turning the free edge from its outwardly flared position to This first step in some cases may be dispensed with, but it has been found desirable with the usual run of 15 blanks. The result of the preliminary. edge bending operation is disclosed in Figures 2 and 11,

and it will be noted that the cross-sectional shape of the skirt edge has been changed just enough to facilitate the next curling operation. 20

The second step in the method comprises giving the edge of the cylindrical flange a substantially semi-circular, inwardly disposed curl, as disclosed in Figures 3 and 12. This step may be performed by a die, such as is disclosed in, 5

locking lugs. The blank after this step has been 5 performed is disclosed in Figures 4, 13, and 14, and the die which performs the step is disclosed in Figurw 21, 22 and 23, and will be described below. The lug forming projections 31 have their outer surfaces 38 disposed on an inclined plane, 40 and extend axially outwardly beyond the adjacent curled portions 28. Since the rolled edge 36 of Figure 3 was notcurled'up at the lug-portions, the edge 36 extends radially inwardly a substantial distance. i

, The final step'in the method comprises bending the incipient lugs 31 into the interior of the 1 cap shell, causing the several surfaces of the lugs to assume a predetermined position, and imparting a slight additional roll to the interme- 5o diate bead portions 28. After this step has been a completed the cap is finished and the bead portions are "in the form of substantially closed tubular sections, as disclosed in Figure 15, and

the lugs are relatively uncurled, or less curled,

as disclosed inFigures 16 to 18 inclusive.

Figures 19to24 show various forms of dies and associated apparatus parts adapted to per form the steps enumerated above.

In the apparatus of Figure 19, a stationary assembly comprises a cylindrical die '55 fixedly secured to the cross-head and having aforming groove 56 on its bottom face. Within a central bore in the die 55 is a rodi'lnormally projected downwardly by compression spring 58. Upon the lower end of the rod is a clamping pad 59 which, as the parts descend, first comes in contact with the interior surface of the top 25 of the cap blank, to hold the blank in position. Surrounding the rod 51, in spacedrelation thereto, and within the d member is 3 d pending sleeve 60 hawng' its lower end provided with a rounded cam surface 6|. Surrounding the sleeve 50, and also within the die 55, is an expanding collet 62 made up of a plurality of spring fingers integral with 5 a ring 63. Each of the fingers adjacent its lower end is provided with an inner cam surface 64 pcsitioned to be engaged by the surfaces! of sleeve 60. Each finger terminates at its lower end in an outwardly projecting head 55. A compression l spring 66 is disposed between a shoulder on fingers 52 and the ring 53 and a flange on the upper end of sleeve 60 to maintain each head 65 in contact with the upper surface of pad 59.

When the die assembly descends the clamping l pad 59 moves inside of the cap blank, and the pad holds the blank upon the nest. Because the spring 53 below the nest is of lighter tension than springs 66 and 5B, the continued movement of the pad 59 depresses the nest and blank into the socket in block 55. Further downward movement, after the nest reaches-the bottom of the socket, is permitted bythe lost motion between rod 51 and cross-head 5i, and by compression of the spring 58. Such downward movement results in relative movement between the sleeve 50 and the fingers 52, and a consequent camming action between their cam surfaces. Thus, each fingeris spread outwardly and the heads move into position to support the inner,

wall of the cap skirt. Immediately thereafter,

the bottom surface of the die 55 comes into contact with the edge of the blank flange and the groove 55 gives it a slight inward bend or nip. The fingers 62 are useful in assuring that 35 the bend is confined to an area closely adjacent the edge of the flange.

When the cross head 54 is raised, the movement of the parts is substantially the reverse of that described above, and the blank is raised to 4a a level substantially equal to the top of the block 59 from which position it may be moved to the next station.

Instead of using a spring premed nest 5i, as disclosed in Figure 19, a one-piece stationary nest Si, disclosed in Figure 24, may be used to advantage. With a two-part assembly such as is disclosed in Figure 19, a minute groove is necessarily present at the juncture between the movable member 5 and the block 55, and this groove results in the formation of a slight rib, or other disfiguring mark, on the exterior of the blank.

' When a one-piece construction is used, this difficulty is obviated.

As a'substitute for the spring pressed blank ejecting means of Figure 19, the nest may be provided with a central here to which is con-- 35 merely imparts a heading to the metal which has already been started in the right direction- This die 58 has a. circular curling groove in its bottom face which has a substantial y semi-circular bottom. It functions to inwardly turn the edge of the fiange to a substantially semi-circular cross sectional curve.

m 21, 22 and 23, a die disclosed Iii which functions to further bard;- or curl certain of the edge of the blank, and to form 75 incipient lugs at other portions. This die performs the important step in the method disclosed in Figures 4,1 3 and 14.

The bottom face of the die is provided with four circumferentially aligned grooves 1|, each of which terminates at its ends in widened por- 6 tions '32. The radially inner wall of each groove at the portions 72 is formed into a. smooth rounded shoulder 13. The grooves merge, at their ends, into 'circumferentially spaced cut-away portions Hi, the bottom surfaces of which have no positive forming action upon the bead. The intermediate grooves H have substantially semi-circular bottoms, as disclosed in Figure 23. A die constructed in substantially this manner operates upon a partially beaded cap shell to complete the 15 head along spaced sections and form enlargements thereon at other points. When the die descends, the grooves II will continue the curling action started by die 68, but since the groove is interrupted at the points 10, this curling action 20 will not be-continued around the entire circumference of the skirt. At the cut-outs T0 the bead will not be rolled up or curled further. However, the tendency to curl imparted to the bead by the die sections II will be transmitted through 25 the material of the .cap skirt to the portions received in the cut-outs III, with the result that the latter portions will be drawn and will bend radially inwardly, as disclosed in Figure 21. These portions of the edge extend radially inwardly beyond the adjacent bead portions, and form projections in the nature of incipient lugs. They are completed, and bent to final form during the next step of the method, by the die disclosed in Figure 24. 58

In the apparatus of Figure 24, expanding fingers 52, similar to the corresponding elements shown in Figure 19, are used. In this case the heads 55' project outwardly under the intumed bead and under the inturned incipient lugs and 4' form an anvil surface which limits the inward axial bending imparted by the die 55" to the lugs. The bottom. face of the die is provided with a. continuous curling surface [5 having a rounded corner 16. The curve [5 between the 45 outer side wall of the groove and the bottom is uniform around the entire circumference, and imparts a uniformlyrounded lower external edge to the cap skirt. Furthermore, it functions to curl the head of the cap a little more, and bends 50 the incipient lugs downwardly intocontact with the members 55', Thus, the bottom edge of the cap skirt is uniformly rounded, and all points thereon lie in a. common plane. The distance between the top of the cap and the thread en- 55 gaging surface of each lug is accurately determined by the upper surface of heads 55'.

An important feature of the method resides in the fact that it is unnecemary in any of the several steps to position theblank in any particuiar angular adjustment with respect to the dies. After the second step the blank is of uniform configuration around the entire circumference of the skirt. After the third step incipient lugs have been formed at certain points. The die of the fourth step has a surface of constant cross sectional shape at all points around its circumference, and the angular position of the blank with respectto the die is immaterial, as eachpoint on the surface of the groove is '10 adapted. to complete the intermediate bead portions or the lug portions.

The cap of the present invention may be made by several alternative: methods. For instance, it is quite feasible to null an inwardly disposed bead, I

' cumference of the skirt, and then unroll certain ternal surface of the bead upon an anvil, and

then applying force to theexpanded die to uncurl the bead. The anvil should have a supporting surface which conforms closely to' the exterior surface of the bead so as to prevent deformation of the lower edge of the cap skirt. The die surfaces could be of any desired conformation and could be given any desired movement, either to flatten or unroll the bead, and the necessary function would be performed in any event, if certain spaced portions of the bead were projected inwardly beyond the adjacent coiled bead portions:

As an alternative method, a particular shape or contour may be given to the lugs by appropriate dies before the lugs are turned inwardly, as disclosed in the aforementioned copending application of Edward M. Enkur, Serial No. 660,927, filed March 15, 1933.

It should be distinctly understood that the present invention is not limited to the details of the cap disclosed herein, nor to the particular method and apparatus described, because many modifications will occur to one skilled in the art after a consideration of the present disclosure. Consequently the invention must be given a scope commensurate with the present contribution to the art, and should be limited only to the methods and articles'described in the accompanying claims, and their equivalents.

We claim: 1. A cap of the lug type having a flange and forming a depending skirt, the flange having its edge portion curled inwardly entirely around the circumferentially spaced points being less curled than adjacent curled portions and forming open portions projecting inwardly from the'skirt beyond the adjacent curled bead portions to provide lugs, the raw edge of the flange at said lugs being turned to present a rounded thread engaging surface and to provide a lug having a reinforced edge. 1

2. A cap of the lug type having a flange and forming a depending skirt, the flange having'its edge portion curled inwardly entirely around the lower end of the skirt to form a substantially closed internal bead except at circumferentially spaced portions, said portions being relatively uncurled and forming open bead portions projecting inwardly from the skirt a greater distance than the bead'thereby providing lugs, the raw edge of the flange at said lugs being turned to provide a lug having a reinforced edge and a rounded thread engaging surface.

3. A closure cap comprising a top, and a downwardly depending uniformly cylindrical skirt terminating in an upwardly turned edge around the entire circumference of the skirt, portions of said inwardly turned edge being rolled upwardly and outwardly toward the inner surface of the skirt to form substantially tubular bead portions, other portions of said inwardly turned edge being rolled a lesser amount and being extended inwardly of said head portions to form locking lugs.

4. A closure cap comprising a top, a downwardly turned skirt presenting a uniform exterior surface terminating in an inwardly turned, uniformly rounded lower edge, portions of the inwardly turned edge being rolled up into substantially tubular bead portions, and other portions thereof being rolled up a lesser amount and projecting inwardly beyond the adjacent bead portions to form locking lugs for engagement with a receptacle, said lugs terminating in rounded thread-engaging ends.

- ERIC B. KRAMER.

EDWARD M. ENKUR. 

